One rule is that girls do not wear kilts. Except FEMALE Highland Dancers.

Another rule is that men do not wear "Dress" tartans. Except MALE Highland Dancers.

Rule you do not wear WHITE stockings with a kilt. Except that kilt rental shops tell you it is acceptable because they don't bother stocking a good selection of kilt hose.

Rule ONLY the Clan's Cheiftan wears the clan crest, all his clansmen wear the crest inside the belt with motto. Except that members of the "Gordon Highlanders" (a Brit military unit) all of them wear the unbelted crest of the Clan Gordon's Cheiftan. So if I'm walking along a trail in Scotland and run into a man wearing the unbelted Gordon Crest I would have no idea wheather to shake his hand, salute, or kneel, depending on if he is a GH vet, currently serving officer or is in fact my Cheif.

Rule the more you know about kilts the more confused you get. Exception: none.